Easy C++ Manual
Copyright © ProAction and APDL, 2001
ANSI functions
All C programs linked to the library STDClib have access to the full range of standard ANSI functions. EasyC is supplied with all 15 header files which declare these ANSI functions. The most useful of these are declared in the 5 header files listed below, and are described in detail in this chapter:
ctype.h stdlib.h math.h string.h stdio.hMany more ANSI functions are declared in the 10 header files listed below. All of these may be used from EasyC, but due to their more advanced nature they are not documented in this user guide. However, the syntax of these functions can be found by studying the header files.
assert.h setjmp.h errno.h signal.h float.h stdarg.h limits.h stddef.h locale.h time.hFurther information about ANSI functions can be found in the Tutorial in the previous chapter, and in most good books on C programming. For the definitive text on the C programming language and descriptions of all ANSI functions you should refer to the IOC/IEC international standard called Programming languages - C (ref. ISO/IEC 9899).
Character Handling
The header <ctype.h> declares several functions useful for testing and mapping characters. In all cases the argument is an int, the value of which shall be representable as an unsigned char or shall equal the value of the macro EOF. If the argument has any other value the behaviour of the functions will be undefined.The behaviour of these functions is affected by the current locale. those functions that have implementation-defined aspects only when not in the "C" locale are noted below.
The term printing character refers to a member of an implementation-defined set of characters, each of which occupies one printing position on a display device; the term control character refers to a member of an implementation-defined set of characters that are not printing characters.
Character testing functions
Name isalnumSyntax int isalnum(int c);
Description Test for any character for which isalpha or isdigit is true.
Returns Nonzero (true) if and only if the argument c conforms to that in the description of the function.
Name isalpha
Syntax int isalpha(int c);
Description Test for any character for which isupper or islower is true, or any character that is one of an implementation-defined set of characters for which not of iscntrl , isdigit , ispunct , or isspace is true. In the "C" locale, isalpha returns true only for characters for which isupper or islower is true.
Returns Nonzero (true) if and only if the argument c conforms to that in the description of the function.
Name iscntrl
Syntax int iscntrl(int c);
Description Test for any control character.
Returns Nonzero (true) if and only if the argument c conforms to that in the description of the function.
Name isdigit
Syntax int isdigit(int c);
Description Test for any decimal-digit character.
Returns Nonzero (true) if and only if the argument c conforms to that in the description of the function.
Name isgraph
Syntax int isgraph(int c);
Description Test for any printing character except space (' ').
Returns Nonzero (true) if and only if the argument c conforms to that in the description of the function.
Name islower
Syntax int islower(int c);
Description Test for any character that is a lowercase letter or is one of an implementation-defined set of characters for which none of iscntrl , isdigit , ispunct , or isspace is true. In the "C" locale, islower returns true only for the characters defined as lowercase letters.
Returns Nonzero (true) if and only if the argument c conforms to that in the description of the function.
Name isprint
Syntax int isprint(int c);
Description Test for any printing character including space (' ').
Returns Nonzero (true) if and only if the argument c conforms to that in the description of the function.
Name ispunct
Syntax int ispunct(int c);
Description Test for any printing character that is neither space (' ') nor a character for which isalnum is true.
Returns Non-zero (true) if and only if the argument c conforms to to that in the description of the function.
Name isspace
Syntax int isspace(int c);
Description Test for any character that is a standard white-space character or is one of an implementation-defined set of characters for which isalnum is false. The standard white-space characters are the following: space ( ' ' ), form feed ( '\f' ), new-line ( '\n' ), carriage return ( '\r' ), horizontal tab ( '\t' ), and vertical tab ( '\v' ). in the "C" locale, isspace returns true only for the standard white-space characters.
Returns Non-zero (true) if and only if the argument c conforms to to that in the description of the function.
Name isupper
Syntax int isupper(int c);
Description Test for any character that is an uppercase letter or is one of an implementation-defined set of characters for which none of iscntrl , isdigit , ispunct , or isspace is true. In the "C" locale, isupper returns true only for the characters defined as uppercase letters.
Returns Non-zero (true) if and only if the argument c conforms to to that in the description of the function.
Name isxdigit
Syntax int isxdigit(int c);
Description Test for any hexadecimal-digit character.
Returns Non-zero (true) if and only if the argument c conforms to to that in the description of the function.
Character case mapping functions
Name tolowerSyntax int tolower(int c);
Description Convert an uppercase letter to the corresponding lowercase letter.
Returns If the argument is a character for which isupper is true and there is a corresponding character for which islower is true, the tolower function returns the corresponding character; otherwise, the argument is returned unchanged.
Name toupper
Syntax int toupper(int c);
Description Convert a lowercase letter to the corresponding uppercase letter.
Returns If the argument is a character for which islower is true and there is a corresponding character for which isupper is true, the toupper function returns the corresponding character; otherwise, the argument is returned unchanged.
Mathematics <math.h>
The header <math.h> declares several mathematical functions and defines one macro. The functions take double arguments and return double values.The macro defined is HUGE_VAL which expands to a positive double expression.
For all functions, a domain error occurs if an input argument is outside the domain over which the mathematical input is defined. The description of each function lists any required domain errors; an implementation may define additional domain errors, provided that such errors are consistent with the mathematical definition of the function. On a domain error, the function returns and implementation-defined value; the value of the macro EDOM is stored in errno .
Similarly, a range error occurs if the result of the function cannot be represented as a double value. If the result overflows (the magnitude of the result is so large that it cannot be represented in an object of the specified type), the function returns the value of the macro HUGE_VAL with the same sign (except for the tan function) as the correct value of the function; the value of the macro ERANGE is stored in errno . If the result undeflows (the magnitude of the result is so small that it cannot be represented in an object of the specified type), the function returns zero; whether the integer expression errno acquires the value of the macro ERANGE is implementation-defined.
Trigonometric functions
Name acosSyntax double acos(double x);
Description Compute the principal value of the arc cosine of x . A domain error occurs for arguments not in the range [-1, +1].
Returns The arc cosine in the range [0, p] radians.
Name asin
Syntax double asin(double x);
Description Compute the principal value of the arc sine of x . A domain error occurs for arguments not in the range [-1, +1].
Returns The arc sine in the range [-p/2, +p/2] radians.
Name atan
Syntax double atan(double x);
Description Compute the principal value of the arc tangent of x .
Returns The arc tangent in the range [-p/2, +p/2] radians.
Name atan2
Syntax double atan2(double y, double x);
Description Compute the principal value of the arc tangent of y/x , using the signs of both arguments to determine the quadrant of the return value. A domain error occurs if both arguments are zero.
Returns The arc tangent of y/x in the range [-p, +p] radians.
Name cos
Syntax double cos(double x);
Description Compute the cosine of x (measured in radians).
Returns The cosine value.
Name sin
Syntax double sin(double x);
Description Compute the sine of x (measured in radians).
Returns The sine value.
Name tan
Syntax double tan(double x);
Description Compute the tangent of x (measured in radians).
Returns The tangent value.
Hyperbolic functions
Name coshSyntax double cosh(double x);
Description Compute the hyperbolic cosine of x . A range error occurs if the magnitude of x is too large.
Returns The hyperbolic cosine value.
Name sinh
Syntax double sinh(double x);
Description Compute the hyperbolic sine of x . A range error occurs if the magnitude of x is too large.
Returns The hyperbolic sine value.
Name tanh
Syntax double tanh(double x);
Description Computes the hyperbolic tangent of x .
Returns The hyperbolic tangent value.
Exponential and logarithmic functions
Name expSyntax double exp(double x);
Description Compute the exponential function of x . A range error occurs if the magnitude of x is too large.
Returns The exponential value.
Name frexp
Syntax double frexp(double value, int *exp);
Description Break a floating-point number into a normalised fraction and an integral power of 2. It stores the integer in the int object pointed to by exp .
Returns The value x , such that x is a double with magnitude in the interval [1/2, 1] or zero, and value equals x times 2 raised to the power *exp . If value is zero, both parts of the result are zero.
Name ldexp
Syntax double ldexp(double x, int exp);
Description Multiply a floating-point number by an integral of power 2. A range error may occur.
Returns The value of x times 2 raised to the power exp .
Name log
Syntax double log(double x);
Description Compute the natural logarithm of x . A domain error occurs if the argument is negative. A range error occurs if the argument is zero.
Returns The natural logarithm.
Name log10
Syntax double log10(double x);
Description Compute the base-ten logarithm of x . A domain error occurs if the argument is negative. A range error occurs if the argument is zero.
Returns The base-ten logarithm.
Name modf
Syntax double modf(double value, double *iptr);
Description Break the argument value into integral and fractional parts, each of which has the same sign as the argument. It stores the integral part as a double in the object pointed to by iptr .
Returns The signed fractional part of value .
Power functions
Name powSyntax double pow(double x, double y);
Description Compute x raised to the power y . A domain error occurs if x is negative and y is not an integral value. A domain error occurs if the result cannot be represented when x is zero and y is less than or equal to zero. A range error may occur.
Returns The value of x raised to the power y .
Name sqrt
Syntax double sqrt(double x);
Description Compute the non-negative square root of x .
Returns The value of the square root.
Miscellaneous functions
Name ceilSyntax double ceil(double x);
Description Compute the smallest integral value not less than x .
Returns The smallest integral not less than x , expressed as a double.
Name fabs
Syntax double fabs(double x);
Description Compute the absolute value of a floating-point number x .
Returns The absolute value of x .
Name floor
Syntax double floor(double x);
Description Compute the largest integral value not greater than x .
Returns The largest integral value not greater than x , expressed as a double.
Name fmod
Syntax double fmod(double x, double y);
Description Computes the floating-point remainder of x/y .
Returns The value x - i * y , for some integer i such that, if y is nonzero, the result has the same sign as x and magnitude less than the magnitude of y . If y is zero, whether a domain error occurs or the fmod function returns zero is implementation-defined.
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